Chair for a vehicle, especially motor car.

The present invention relates to a chair for a vehicle, particularly a motor vehicle, as defined in the preamble of claim 1. Such a chair is known from BE-A-900 876.

A major aim of the present invention is to provide a chair of the aforementioned type to remove or at least mitigate a very effective back pain passenger vehicle, caused by the vertical oscillations of the chair induced example by inequalities of the road in the case of a motor vehicle.

It was found that a wrong choice of the characteristics of the mobile part of the file had an adverse effect on the back of the passenger instead of the desired beneficial effect.

For example, if the natural frequencies of the loaded seat passenger and the movable part of the folder are approximately equal there is a resonance phenomenon, so that the oscillation of the movable part of the case may have a much higher amplitude than seat passenger charge.

To solve this problem it has been proposed to chair the inertia of the moving part of the record was as low as possible.

Although favorable results were obtained by this solution, it was found that the practical implementation, especially on an industrial scale with a chair with respect thereto, may be quite complex.

A major aim of the present invention is to provide an aforementioned type of chair of a very simple construction which, without requiring special care, from the perspective of material selection and arrangement of the constituent parts of the file, delete or least significantly reduce back pain passenger.

To this end, according to the invention, the part of the seatback against which the back rests, is arranged to rest on the resilient members which comprise at least one helical spring fitted on a guide rod extending in the direction of upward and downward movement supra, this rod being fixed relative to a part of the backrest and slidable relative to each other along said direction part.

Other details and particularities of the invention will emerge from the description given hereinafter by way of non-limiting example of a particular embodiment of a chair according to the invention.

Figure 1 is a schematic side view of a chair according to this particular embodiment of the invention.

Figure 2 is, on a larger scale, a longitudinal section of an essential part of the chair according to this particular embodiment.

In both figures, the same reference numerals relate to identical elements.

The main object of the present invention is to present a chair to the vehicle in which the relative importance of the effect of inertia has been modified compared to other factors.

Indeed, it was found according to the invention, based on tests and measurements on both fully fixed back seats to record at least the part intended to come into contact with the back of the passenger is movable, that the most harmful frequencies for the spine are located beyond 10 Herz.

It was also concluded that it is not always necessary that the mobile part of the record, against which rests the back of the passenger, have a low inertia.

The vibrations to which is subject the spine of a passenger vehicle, particularly a motor vehicle, are due to floor vibration on which is fixed the chair in which is seated passenger.

Next inventon the present, the main quality that must have the entire chair, that is to say, the seat and back, is that the construction should be such that vibrations of the vehicle floor, with a higher frequency 10 Hz, do not reach the spine of the passenger.

Usually, the seat of a vehicle seat has a fairly soft suspension to ensure passenger comfort. Typically, the suspension has stiffness or rigidity of 15 to 30 kg / cm. Such a suspension, loaded with a passenger weighing about 75 kg strongly dampens vibrations having a frequency higher than 10 Hz. In addition, the morphology of the human body is such that the fleshy parts of the seat passenger are a good shock absorber for frequencies above 10 Hz. a total vibrations of a frequency greater than 10 Hz the floor of a vehicle, particularly a motor vehicle, will substantially not transmitted to the spine of the passenger through the seat the chair in which sits the passenger.

By cons, if the folder is not moving or if it has no moving parts to the back of the passenger, vibration beyond 10 Hz are not amortized, and the floor vibration can therefore achieve column spinal passenger through the folder.

In general, the invention relates to a chair for use in any type of vehicle, including automobile, bus, truck, tractor etc ...

A particular embodiment of a chair according to the invention, having the characteristics described above has been shown in the appended figures.

This chair comprises a seat 1 and a backrest 2, which preferably is hinged to the rear part of this seat.

In the case of a car, bus or truck, seat 1 is fixed, possibly slide horizontally on the floor of the vehicle 3. Since there are traditional fixing means, these have not been shown in Figure 1.

At least part 4 of the case 2, which rests against the back of a person riding in the chair cooperates with elastic members 5 to thereby allow movement of this part 4 in the same direction along a movement up and down, as indicated by the arrows 6, relative to the seat 1.

This chair is characterized in that the elastic members 5 have a low stiffness whose value is less than 1 kg / cm and is preferably between 0.01 kg / cm and 1 kg / cm.

In the embodiment shown in the figures, part 4 of the case 2, which rests against the back, is arranged to rest on the elastic members 5 and to be guided in the direction 6 of the up and down movement.

Specifically, virtually all the file is mounted so as to undergo this up and down movement relative to the seat 1.

Thus, in this particular embodiment, the lower part of the backrest 2 cooperates, by intremédiaire elastic members 5, with a support 8 which is preferably mounted on the rear part of the seat 1 by means of an articulation 9, allowing to adjust the backrest relative to the seat.

As clearly shown in Figure 2, also in this particular embodiment, the elastic members 5 are constituted by a helical spring fitted on a guide rod 10 extending along the direction of upward and downward movement of the backrest 2, as indicated by arrow 6.

One end of this rod 10 is fixed relative to the movable part of the backrest 2, the other end being slidably mounted in the support 8 in the direction of arrows 6.

In practice, as shown in Figures, the case 2 can comprise a metal frame consisting for example a U-shaped tube 11 reversed in each of the two free ends 12 which is fixed a rod 10.

The support 8 may consist of two tube pieces 16, whose lower end is secured to the articulation 9, so as to be blocked in an adjustable angular position relative to the seat, and whose upper end is provided a tubular slide 17 to beads 18 in which can slide the rod 10 with a minimum of friction.

Finally, a sleeve 19 of soft rubber connects the facing ends of the armature 11 and tube ends 16, thus covering the spring 5 and the rod 10.

The spring 5 allows the mobile part 4 of the file to oscillate around a fixed point relative to the seat 1, the fixed point corresponding to the position occupied by the file when the vehicle stops.

Thus, the lumbar support 7 of the mobile part 4 of the backrest 2 correctly follow the oscillating movements of the back of the passenger. This is for example not the case if the movable part is constituted by a single endless belt mounted around idler rollers.

The frame 11 may be filled with a molded cushion 13 of foam, for example, against which the back can be supported, and a headrest 15 arranged on the upper part of the armature 11.

Given the pressure of the back of a person sitting in the chair against the part 4 of the case 2, the latter will follow exactly the oscillating up and down movement of the back of the passenger.

It is understood that the invention is not limited to the embodiment described above and that many variants can be envisaged without departing from the scope of the claimed protection.

Thus, in some cases, the file is not hinged on the seat.